There were conflicting reports. The Interfax news agency described the event as a meteor shower, a spokeswoman for Russia's Emergency Ministry, told the AP. But the Interfax news agency described the incident as a single meteorite.

"It was definitely not a plane," an emergency official told Reuters. "We are gathering the bits of information and have no data on the casualties so far."

RT quotes witnesses who say the blast and unusual spectacle overhead had some residents fearing a UFO.

"My windows were not smashed, but I first thought that my house is being dismantled, then I thought it was a UFO, and my eventual thought was an earthquake," Bukreeva Olga wrote on Twitter, according to the news site.